There is a detection circuit configured to detect presence or absence of a conduction angle control of an AC voltage and the type of the conduction angle control. There is a power circuit including the detection circuit and configure to perform control in accordance with a result of detection by the detection circuit to supply power to a load. The power circuit of this configuration is used in a luminaire provided with a lighting load including illumination light sources such as light-emitting diodes (LEDs), for example. In the detection circuit, it is desired to enable a determination of the presence or absence of the conduction angle control and the type of the conduction angle control with a simpler circuit.